Outboard motor unit with inclined steering axis



March 27, 1956 E, c, KIEKHAEFER 2,739,561

OUTBOARD MOTOR UNIT WITH INCLINED STEERING AXIS 2 Sheets-Sheet 1 FiledOct. 8, 1951 m w W Mm Z r w March 27,1956 c. KIEKHAEFER OUTBOARD MOTORUNIT WITH INCLINED STEERING AXIS 2 SheetsSheet 2 Filed Oct. 8, 1951OUTBOARD MOTOR UNIT WITH INCLINED STEERING AXIS Elmer C. Kiekhaefer,Cedarburg, Wis.

Application October 8, 1951, Serial No. 250,261

7 Claims. (Cl. 115-18) This invention relates to outboard motor unitsfor boats and particularly to steering of the boats by turning the motorunits.

The invention provides improved motor operation wherein the propellerthrust which is directed forwardly in normal operation is directedangularly downwardly to a degree varying with turning of the motor unitin steering the boat to the right or left.

An object of the invention is to enhance the personal safety of theoccupants of the boat and particularly to prevent swamping of the boaton turns and in reverse by a lifting of the stern of the boat efiectedby the motor in operation.

A more particular object is to direct the propeller angularly downwardlyto a varying degree corresponding with the degree of turning movement ofthe motor unit to effect a corresponding degree of lifting of the sternof the boat in relation to the forward thrust of the propeller.

These and other objects and advantages will be more fully set forth inthe following description of a preferred embodiment of the invention asillustrated in the accompanying drawings.

In the drawings:

Figure 1 is a side elevation of the stern of a boat and States Patent Qthe motor unit as attached thereto and driving the same 1 Fig. 4 is alongitudinal vertical cross-section through the bracket of the motorunit by which the latter is removably secured to the transom of the boatas shown in Figs. 1 through 3; and

Fig. 5 is a longitudinal vertical cross-section of underwater gear'caseof the motor unit.

The outboard motor unit shown in the drawings includes the cowl 1 whichsubstantially encloses the engine 2 of the motor at the upper end of theunit. The housing 3 supporting engine 2 extends downwardly thereof andrigidly connects the engine 1 and the lower gear case 4 disposed underwater. The propeller 5 is mounted on the shaft 6 supported by the gearcase 4 and is driven by engine 1 and normally disposed underwater topropel the boat 7 forwardly and effect the steering of the boat as willbe described.

The drive shaft 8 extending downwardly within housing 3 is connected atthe upper end to the lower end 9 of the engine crankshaft. The lowerportion of shaft 8 is journally supported by the bearings 10 in gearcase 4. The bearings 11 in gear case 4 support shaft 6 normallyhorizontally to carry the propeller for operation in the water. Thedriven gear 12 is mounted on shaft 6 to mesh with the drive gear 13which latter is fixed on the lower end of shaft 8.

The motor support bracket 14 includes the clamp the screws 15 by whichthe bracket is secured to the transom 16 of boat 7, and the swivelbracket member 17 which is pivotally assembled on the transversehorizontal pin 18 of bracket 14. In operation, the-motor unit issupported by member 17 with the propeller 5 disposed under waterrearwardly of the boat, and is adapted to be tilted on the axis of pin18 to allow the propeller to be lifted to pass over submerged objects orto be withdrawn from the water.

The tilt lock latch 19 is carried by member 17 and includes thetransverse pin 20 which is selectivelydisposed in any of the series ofrecesses 21 formed in bracket 14. The forward face of each recess 21 isformed to secure the motor against tilting in a direction which wouldlower the propeller and the opposite faces are pitched or inclined tolift pin 20 out of the recesses upon tilting of the motor in theopposite direction. The handle 22 secured to latch 19 provides for theadjustment of pin 20 in the selected recess and provides for therelativeadjustment of the motor unit end bracket 14 to accommodate various boatshaving transoms of different rake or angularity.

The directional control'of the boat, in each case, is effected byturning the motor unit on a substantially vertical axis to change thedirection of propeller thrust. In the motor unitshown, housing3iincludes the cylindrical portion 23 which is journally mounted in theupper and lower bearings 24 and 25 carried by the sleeve of member 17.Bearings 24 and 25 include the rubber portions 26 which provide for thecushioned support of the motor unit. Steering of the boat is effected bymanipulating the tiller handle 27 which turns the motor unit on thenear-vertical axis of bearings 24 and 25 to direct the propeller thrustto the right or left.

According to the invention the axis of bearings 24 and 25 isinclined'forwardly, or more specifically the axis lies in a verticallongitudinal plane respecting the boat and forms above a horizontalplane an acute angle therewith forwardly of the axis. In the motor unitshown, the axis of bearings 24 and 25 is inclined forwardly about 12 anddefines an angle with the horizontal of about 78. The drive shaft 8 issimilarly inclined and extends within housing 3 on the axis of bearings24 and 25 and the steering axis of the motor unit. Within the scope ofthe presently claimed invention the motor unit may be supported forsteering movement on an inclined axis which is forwardly of the driveshaft and housing which latter may extend generally vertically or beotherwise inclined.

The angularity of the axis provides for tilting of the v propellerdownwardly as the motor unit is turned to the right or left as shown inFig. 2. The degree to which the propeller is directed downwardly varies(not directly) with the degree of turning movement of the motor unit. Insteering the boat, the propeller accordingly tends to lift the rear ofthe boat whenever a turning of the boat is effected and helps toprevent, particularly on sharp turns, upsetting or swamping of the boat.

The invention provides a factor of safety in making turns at high speedswhile providing a horizontal thrust and maximum propeller efficiency inthe forward direction. The plate-28 secured to gear case 4 is disposednormally horizontally above the propeller and operates to preventcavitation and to assure the full efiiciency of the propellerparticularly as when operating near the surface of the water In steeringthe boat by turning the motor unit, plate 28 is adjusted to correspondwith the times the water pushed back by the transom tends to pass overthe transom and'into the boat. The maximum angularity downwardly ofpropeller provided by the invention is reached when the propeller is inthe full reverse position referred to and provides at such times maximumprotection against swamping of the boat.

When in the reverse position, the latch 19 is engaged within the slot 29of housing 3 which latter secures latch 19 and pin 20 in the selectedrecesses 21 of bracket 14 to prevent raising of the propeller whileoperating in reverse.

Various embodiments of the invention may be em ployed within the scopeof the following claims:

I claim:

1. In a dirigible outboard motor unit including a propeller disposedunderwater to direct the thrust of the propeller normally horizontallyand to drive the boat forwardly, a bracket adapted to be removablysecured to the transom of a boat and including a pivotal connectionsupporting said motor unit for pivotal movement on a steering axiswhereby the propeller can be adjusted for the directional control of theboat, said axis approximately intersecting the axis of said propellerand defining forwardly therewith an acute angle whereby the thrust ofsaid propeller is directed angularly downwardly to lift the stern of theboat simultaneously with the directional control of the boatin eitherdirection.

2. In a dirigible outboard motor unit including a propeller disposedunderwater to direct the thrust of the propeller normallyfhorizontallyand to drive the boat forwardly, an anti-cavitation plate rigidly fixedto said unit immediately above said propeller, and a bracket adapted tobe removably secured to the transom of a boat and including a pivotalconnection supporting said motor unit for pivotal movement on a steeringaxis whereby the propeller can be adjusted for the directional controlof the boat, said axis approximately intersecting the axis of saidpropeller and defining forwardly therewith an acute angle whereby saidanti-cavitation plate and the thrust of said propeller are directedangularly downwardly to lift the stern of the boat simultaneously withthe directional control of the boat in either direction.

3. In a dirigible outboard motor unit including a propeller and a shaftsupporting said propeller underwater; said shaft and propeller beingdisposed to direct the thrust of the propeller normally horizontally andto drive the boat forwardly, a bracket adapted to be removably securedto the transom of a'boat and including a pivotal connection supportingsaid motor unit for pivotal movement on a steering axis whereby thepropeller can be reversed to drive the boat rearwardly, said axisapproximately intersecting that of said propeller shaft and definingforwardly therewith an acute angle whereby the thrust of said propelleris directed angularly downwardly to lift the stern of the boatsimultaneously with the reverse propulsion of the boat to avoid swellspassing over the transom into the boat.

4. In a dirigible outboard motor unit including a propeller disposedunderwater to direct the thrust of the propeller normally horizontallyand to drive the boat forwardly, an anti-cavitation plate rigidly fixedto said unit immediately above said propeller, a clamp bracket adaptedto be removably secured to the transom of a boat, a swivel bracketincluding :a pivotal connection supporting said motor unit for. pivotalmovement on a steering axis whereby the propeller can be adjusted forthe directional control and reverse propulsion of the boat, said axisapproximately intersecting the axis of said propeller and definingforwardly therewith an acute angle whereby said anti-cavitation plateand the thrust or said propeller are directed angularly downwardly tolift the stern of the boat simultaneously with the directional controlof the boat in either direction, said swivel bracket being supported bysaid clamp bracket for tilting of the motor unit to allow the propellerto be raised for passing over submerged obstructions, and interlockmeans connecting said brackets to prevent tilting of the motor unit whenin the position effecting the re verse propulsion of the boat.

5. in an outboard motor unit comprising an engine, a propeller and ashaft for supporting said propeller underwater, a drive shaft and gearmeans connecting said engine and said propeller shaft to drive thepropeller, said shaft and propeller being disposed to direct the thrustof the propeller normally horizontally and to drive the boat forwardly,and a housing for said drive :shaft supporting said engine and saidpropeller shaft; a bracket adapted to be removably secured to thetransom of a boat and including a pivotal connection supporting saidmotor unit for pivotal movement on a steering axis approximatelyintersecting that of said propeller shaft anddefining forwardlytherewith an acute angle whereby the thrust of said propeller isdirected downwardly to lift the stern of the boat simultaneously withsteering movement efiecting the directional control of the boat in otherthan the forward direction.

6. In an outboard motor unit comprising an engine, a propeller and ashaft supporting said propeller under water, a drive shaft and gearmeans connecting said engine and said propeller shaft to drive thepropeller, said shaft and propeller being disposed to direct the thrustof the I angle whereby said anti-cavitation plate and the thrust of saidpropeller are directed angularly downwardly with a correspondingsteering movement elfecting the directional control of the boat toliftthe sternof the boat in other than the forward direction.

7. 'In an outboard motor, the combination with a bracket support havinga swivel bearing with its axis forwardly inclined from the vertical, ofa propulsion unit rotatably'mounted on the swivel bearing and freelyrotatable through at least of movement between forward propulsion andreverse propulsion positions and comprising in substantially rigidconnection a power head, a strut and a gear casing, the power headincluding an engine having aldrive shaft extension through said strutand the gear casing being provided with a propeller shaft and propeller,the drive shaft and propeller shaft having meshed gears in'said casingand being at an obtuse angle to each other such that the rotation ofsaid unit on said bearing to a position for reverse propulsion will movethe propeller shaft about said inclined axis to direct down- I wardly asubstantial component of its thrust.

References Cited in the file of this patent

